The purpose of this project is an in depth investigation into the thymus derived lymphocyte (T cell). The central approach is the in vitro propagation of cell lines which express T cell characteristics and provide substantial quantities of such cells and their products. Two types of murine T cells, those functioning in delayed hypersensitivity to soluble antigens, and those sensitized against minor histocompatibility antigens, will be isolated by sedimentation at unit gravity (micro STAPUT). Cells so purified will be analyzed with regard to stage in the cell cycle, antigen expression, antigen binding, and function (cytotoxicity, blast transformation). Interactions (amplification, suppression) between cells from different areas of the micro STAPUT will be studied. An ongoing investigation into the functional capabilities and membrane properties of murine T cell lymphomas, particularly S49.1TB2, EL4.BU and WEHI 22, will be continued. These transformed T cells will be compared with different sources of primary T cells, such as thymocytes, lymph node T cells, and purified, antigen-sensitized T cells. Continuously propagatable T cell lines with specificity for individual antigens, will be established by means of somatic cell hybridization of micro STAPUT purified, antigen-sensitized T cells with S49 or EL4. Biochemical markers will permit hybrid isolation in selective medium. Previously established lymphomas will also be screened for their ability to react to H-2 antigens expressed on fibroblasts. Receptor analysis and activation studies will be carried out on such antigen-specific T cell lines.